Drill press speed reducing assembly



April 24, 1951 s. KRAFKA 2,550,012

DRILL PRESS SPEED REDUCING ASSEMBLY Filed April 15, 1949 2 Sheets-Sheet l /III Ill/IIIIIQ- April 24, 1951 s. KRAFKA DRILL PRESS SPEED REDUCING ASSEMBLY 2 sheet's sheet- '2 Filed April 15, 1949 IfiENT R 52% 1% arm 21 and 28 is formed with an elongated slot 32 extending lengthwise of said arms. Each pulley 25 and 25 is provided with a central bearing 33 which turns on a shaft 34 having its lower end clamped in place lengthwise of said slot 32 by means of a clamping nut 35. In order to distribute lubricant to the space between the bearing and the shaft, the latter is provided with the passage 35 leading from the upper end of the shaft into a space'3l provided in the side wall of the shaft. Lubricant supplied by a cup 38 fitted to the upper end of the passage 3% is accordingly conducted to the shaft ing associated with each pulley 25 and 2 5.

In'order to establish a driving connection between the pulleys 20 and 22 via the 26, with a view to obtaining a v suitable for operation of comparatively large tools from a conventional motor l 8 in accordance with the present invention, a belt 33 is trained about the smallest step of pulley 20 and the largest step of pulley smallest step' of pulley 25 to the largest step of pulley 25 and a belt 4! is connected from the smallest step of pulley 25 to the largest step of spindle pulley 22. The speed of the spindle pulley 22 is accordingly reduced in the ratio of to l and the bearpulleys 2'5 andv speed reduction 26, a belt 49 is connected from the relative to the speed of the motor pulley wherer by a spindle speed of 90 to 100 revolutions per minute is'obtained to accommodate use of drills up to 1 inch diameter and boring tools of a size as large as 3 /2 inch diameter without danger of damaging the tool.

Due to variations in the design and construetion of drill heads of certain types of drill presses, the clearance available about the spindle pulley is sometimes insul ficient to accommodate an arrangeinent of belt drives as shown in Fig. 1. In connection with drill presses such as the type shown in Fig. 4, an arm 45 extending upwardly andforwardly from the head 46 to provide a bearin in upward vertical alignment with the axis of the spindle pulley 45 would interfere with a belt drive such as represented by the belt 4| shown in Fig. 2. In such a case the present invention contemplates the use of a stub column member 48 adjustably clamped in a slot 49 provided in the outer end of an arm 50, which arm is fastened to the main column 5| of the press by a clamp 52. The stub column member 48 accordingly provides a support for a pair of pulley supporting arms 53 and 54, corresponding to the pulley supporting arms 21 and 28 shown in Figs. 1' to 3 inclusive. As shown in Fig. 5 and Fig. 6, each arm 53 and 54 has a yoke portion 55 clamped to the member 43 by means of clamping bolts 55,

with the arms 53 and 54 extending along a line in spaced parallel relation to a line joining the spindle pulley 4'1 and a pulley 51 on the shaft of the motor. A pulley 58 mounted on the arm 53 and a similar pulley 59 mounted on the arm 54 thus provide speed reducing means between the spindle pulley 41 and the motor pulley 51, with the pulleys 58 and 59 so positioned relative there-- to aste accommodate a belt connection 60 between the smallest step of pulley 59 and the largest step of spindle pulley 4! without interference by the arm 45 extending from the head A belt 6| connecting the smallest step of 46. pulley 58 and the largest step of pulley 59, and a belt 62 connecting the smallest step of motor pulley 51 and the largest step of pulley 58 accordingly operate to reduce the speed of the spindle pulley 41 in the ratio of about to 1 relative to the motor pulley 51. It will be noted that'each of the pulleys 41, 51, 58, and 59 is of the five step cone type and that the arm connected to the main column 5| of the press is offset downwardly at the end thereof carrying the stub column member 48 whereby the steps of the supplementary pulleys 58 and 59 may be maintained in horizontal alignment with the steps of the pulleys 41 and 51.

It willbe understood, of course, that the variations in 'thespeed of the spindle, with reference to the pulleys shown in Figs. 1 to 3 inclusive as well as the pulleys shown in Figs. 4 to 6 inclusive,

"may be accomplished by changing the belts to different stages 'of the pulleys.

The slots in the arms supporting said pulleys provide for any ad- 'justment needed in the position of the pulleys to accommodate removal of the belts from one stage or step to another stage or step of the pulleys.

It is believed that the gnany advantages of a drill press attachment constructed in accordance with the present invention will be readily understood, and although a preferred embodiment of the device is as illustrated and described, it is to be understood that changes in the details of construction and in the combination and arrangement of parts may be resorted to which will fall within the scope of the invention as claimed. What is claimed is:

1. In a drill press, the combination of a column,

'a drill head supported on said column, a drill spindle on said drill head, a motor, and means connecting the motor and said drill spindle including a multi-step pulley on said drill spindle and a multi-step pulle on'the shaft of said motor, and a pair of supplementary multi-step 1 pulleys, each of said supplementary pulleys being supported in laterally spaced relation to said drill head for rotation about an axis in spaced parallel relation to the axes of said other pulleys,

a belt connecting said pair of supplementary multi-step pulleys, a belt connecting the pulley on the shaft of the motor and one of said supplementary pulleys, and a belt connecting the pulley on the spindle and the other of said supplementary pulleys.

2. In a drill press as defined in claim 1, including an arm supporting one of said supplementary pulleys and a second arm supporting the other of said supplementary pulleys, each of said arms being secured to the other in clamping relation to the column of the press.

3. In a drill press as defined in claim 1, in -1' cluding an arm having an elongated slotted outer end portion in which one of said supplementary pulleys is adjustably supported and a second arm having a similar slotted outer end portion in which the other of said supplementary pulleys is adjustably supported, the end of each arm remote from said slotted'end being secured to the other in clamping relation to the column of the press.

4:. In a drill press as defined in claim 1 including an arm secured to and projecting laterally from said column of the press, a stub column member carried by the outer end of said arm, a second arm supporting one of said supplementary" pulleys, and a third arm supporting one of the other ofsaid supplementary pulleys, said second and third arms each being secured to the other in clamping relation to said stub column member. H 5. In a drill press as defined in claim 1 in-' cluding an arm secured to and projecting laterally from said column of the press, said arm'having its outer end olfs'etidownwardly in relation to the end thereof secured to said columnar the' press, a stub column membercarried by the outer pulleys is adjustably supported and a second arm 10 having a similar outer end portion in which the other of said supplementar pulleys is adjustably supported, the end of each arm remote from said slotted end having a yoke portion adapted to em- 6 brace the column of the press through an arc of substantially 180 degrees, said yoke portions being bolted, one to the other to secure said arms in clamping relation to said column of the press.

STEFAN KRAFKA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,022,756 Rice Apr. 9, 1912 2,073,704 Mitchell Mar. 16, 1937 

